Screw jack



April 13, 1926.

W. THATCHER SCREW JACK Filed August 28, 1925 2 Sheets-Sheet 1 April 13 192.6. 1 1,580,348

' W. THATCHER SCREW JACK Filed August 28, 1925 2 Sheets-Sheet 2 Patented Apr. 13, 1926.

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Application m August 2s,-1a25. semi m. 53,111.

To all whom it may concern.- 1 Be-it known that I, WALTERTHATCHER, a citizen of'the United States, residing at Chicago, in the'cou-nt-y ofCook and State'of Illinois, have invented certain new and useful Improvementsin Screw Jacks, of which the following is a specification. This invention relates to improvements in screwjacks designed for manual operation, the construction :of the jackbeing such that it is capable of employment-in quarters ordinarily-difficult ofaccess. A further object isto provide a jack that is easy to operate, that is compact in assembly and that can be manufactured at a minimum cost.

With the foregoing andother objects in view the, invention consists in the combina tion and arrangement of parts to be hereinafter fully described, pointed out inthe appended claims and illustrated in the accomp'anying drawings which form a part of this application and in which Fig. 1 is a perspective view of the jack,

part of the. operating handle being elimig nated.

Fig. 2 is a fragmentary sectional view showing the jack under a load. 2

Fig. 3 is an enlarged fragmentary sectional view showing the means, for locking the stationary screw shaft at its base.

Fig. 4 is an enlarged fragmentary sectional view showing the power transmission mechanism between the handle and riser.v Fig. 5 is across section taken on line 5-5 of Fig.4.

Figs

hicle eventhough'the wheels are up to the hubs in mud, sandfor water. The jack 'comv Rotation of the crank 32 will now-rotate prises a base whereupon uprights are supported that carry slides connected to a riser operative over a stationary screw shaft that is bevel-gear-connected to the operating han- 6 and 7 are sectional detailviews of the operating handle.

centrally disposed longitudinall rib .5 that seats "in the longituthnal groove G'formed ineach of the slides 7, and forms azguide fori said slide in its movement. A wehSconnects each slide '7 and the riser. 9

- extending I which latter member .encompassesthe s'tationary screw shaft 10't-he base 11. of which restsupon the. base 1 and is received in the block 12150 whichx'it screw 13.

The riser 9 at tween-its terminal "flange l4and collar.15 thehead 16 that receives the :load .17, .said head preferably having its edges'notched orflnted to receive a chain 18' that is someis secured by; the: set

end receives, j

times usedand :that carries the' book 19 at one end and is secured to the hook 20 as its opposite end, said book 20 being fastto the riser. r I

The lower, end of the riser is. supported upon a platform 21 arranged upon ball beararranged upon the screw shaft 10, said bevel ear being in mesh with the bevel pinion 23 the shaft 24 of which is received in and releasably connected to the socket member 25, said socket member and shaft 24 having meetin'gflat faces 26 and being connected together by thescrew27 yieldingly retained ings carried by the bevel gear 22 operatively in position by the flat spring 28 secured at 7 one end to said socket member by the pin 29.

The socket member, is connected by the universal joint 30. to the tubular link 31 that at its opposite end receives one end of the crank 32 formed with groove 32 and releasablysecured thereto by the screw 33 and spring 34, said crank 32 bein provided with a tubular hand grip 35. 11% 36 mounted upon the shaft 24 has-its ends secured to the web .orslides to hold said shaft and the pinion 23' in place. ,In operation the head 16 is placed beneath the. load when the riser is in lowered position upon the screw shaft, or the hook 19 may be plac 18 passed over the head as shown in Fig. 1.

the bevel pinion 23 and bevel gear 22-which will travel over the screw shaft 10 and cause the riser 9 and slides 7 to travel upward over oke l y ed in engagement with the load with the chain said shaft lO thus raising the load. Rota- 5 operatively engaging said uprights, a riser encompassing said shaft, connection between said slides and shaft, a head carried by .said w.

riser, and manually operable means connecting said shaft and riser for actuating the latter.

2. In a screw jack, a base, uprights carried thereby, a stationary shaft upon said base, slides operative-1y engaging said uprights, a riser encompassing said shaft, a head for said riser, connection between said slides and shaft, a chain connected to said riser for engagement with said head, a hook carried by said chain, and manually operable means connecting said shaft andriser for actuating the latter.

3. In a screw jack, a base, uprights carriedthereby, a stationary screw shaft upon said base, slides operatively engaging said uprights, a riser encompassing said screw shaft, ahead for said riser, a bevel gear ops eratively arranged. upon said screw shaft in supporting engagement with said riser,

a shafted bevel pinion in mesh with said bevel gear, a yoke connecting. said bevel pinion shaft and the aforesaid slides, a crank handle, and connection between said crank handlev and the shaft of said bevel pinion.

4. In a screwjack, a base, uprights carried thereby, oppositely disposed ribs formed upon said uprights, a stationary screw shaft 'upon'said base, means for securing the lower crank handle, and connection between said handle: and the shaft of said bevel pinion.

In testimony that I claim the foregoing as my own I have hereto affixed my signature.

' WALTER THATCHER. 

